For more than a dozen years, astronomers have been designing a unique new telescope: an oval-shaped ring of 40 antennas that would open up a little-explored part of the spectrum to "see" everything from extrasolar planets to the formation of galaxies. Next month, Science has learned, their efforts will come one step closer to reality when the Clinton Administration requests money to begin work on the $200 million Millimeter Array (MMA).

The array's big payoff would come from its ability to detect electromagnetic emissions at millimeter and submillimeter wavelengths, the part of the spectrum between infrared and radio waves. This portion of the spectrum provides a glimpse into the cool interstellar dust and gas clouds that tell volumes about both the present and early universe but are opaque to optical telescopes. And it's been largely off limits to radio astronomers, who are confined to either smaller, less powerful millimeter instruments or telescopes in the centimeter range.

The MMA "will be unique in its capacity to probe vast areas of the universe with 10 times the resolution and 100 times the sensitivity of existing arrays," says Richard Simon of the National Radio Astronomical Observatory in Charlottesville, Virginia, which wants to build the telescope. "There are a huge number of astronomical problems that this [capability] opens up." Anneila Sargent, director of the Owens Valley Radio Observatory operated by the California Institute of Technology, calls the MMA "a new window into the universe. Its time has come," she says.

The project would be funded by the National Science Foundation (NSF), which will request $25 million over 3 years to build and test a prototype array with two antennas and a receiver. If all goes well, NSF would then seek additional money to build and install the full array by about 2005. NSF would like international partners to put up between 25% and 50% of the total construction and operating costs in return for a share of observing time, but so far it has no takers. For more details on the MMA, Science Online subscribers can link to the News[2] story in tomorrow's Science.